Where there is no regular licensed sport hunting permitted by law, the following urban deer management approaches have been used.
Lethal Methods: Widely Used and Safe
Professional culls using trained sharpshooters with firearms. These typically attract deer with bait, use pre-planned shooting lanes, frangible ammunition that does not ricochet, aiming down from a natural elevation or stand, and using silencers on rifles.
Ann Arbor uses culls by sharpshooters in selected parks and on private property.
Managed hunts with firearms or archery. These require the vetting of hunters. Ann Arbor has used archery hunters to control deer at the Ann Arbor Municipal Airport.
Less common lethal methods:
Capture via trapping, followed by euthanasia. Trapping is time consuming and is stressful for the deer.
Capture via darting, followed by euthanasia: Used where otherlethal methods are impractical. One objection, however, is that the anesthesia in the darting drug used to immobilize the animal has no time to clear and makes the meat unfit for human consumption. Capture by darting, followed by euthanasia, is not currently permitted in Michigan.
Several nonlethal fertility control approaches have been used. Note that though the population growth is slowed or stopped, the deer are not removed. Thus any existing deer conflict is not resolved. To be effective, a very high percentage (>95%) of does must be treated.
Tubal ligation of does: This surgical procedure of cutting the fallopian tubes is rejected now because the does continue to have their estrus cycles. This attracts and agitates the bucks.
Ovariectomy: Does are captured via darting, moved to a surgical station, and the ovaries are surgically removed. Does are then returned to the location where they were darted. This was used in three Ann Arbor neighborhoods where lethal methods were not feasible. This procedure is, however, not currently permitted in Michigan.
Vasectomy. This surgical procedure for male sterilization removes the pathway for sperm. It is only practical in locations with limited deer access like islands or enclosed landscapes. It is currently being implemented in Staten Island, New York City.
Doe immunocontraceptives. These are non-hormonal drugs that prevent fertilization. They include PZP and Gonacon. These immunocontraceptives have been used in multiple experiments over several decades but are still only approved for research. They are difficult to administer and require a booster shot to maintain their efficacy. In almost every location that immunocontraceptives have been tried (e.g. Fire Island National Seashore, Cleveland Metroparks, NIST), eventually the site abandoned their use. Immunocontraceptives for deer fertility control are not currently permitted in Michigan.
Relocation: Capturing and moving deer is not permitted in Michigan. It traumatizes the deer and many of them die due to capture myopathy. Relocating deer also spreads deer diseases, an important concern with Chronic Wasting Disease (CWD) and Epizootic Hemorrhagic Disease (EHD) both occurring in Michigan.
Limiting Deer Damage
There are several techniques for reducing deer damage. These can work in a smaller yards, but they are not applicable to large scale natural areas. And they are displacement techniques – they just shift the deer to other locations for food. The deer still need to eat, be it in your neighbor’s yard or a park.
“Deer resistant” plants. Deer prefer some plants over others. But these preferences diminish as deer population increases and the deer become hungrier as food is harder to find. Most of the non-preferred plants are non-native and do not support the native pollinators. These non-natives are also potentially invasive and are not an option for Ann Arbor’s natural areas. Ann Arbor’s deer management site lists some “deer resistant” plants: Deer resistant gardening. This is a displacement technique – it just shifts the deer to other locations for food.
Traffic warnings, such as deer crossing signs. This may prevent some accidents by encouraging caution and slower speeds, but studies have shown the signs are not effective long-term. And the deer ignore the signs and cross wherever they want.
Fencing and plant netting can protect specific plants or a yard but must be of sufficient height (deer can easily jump 8+ feet), which can be in conflict with local ordinances. Fences are expensive and merely move the deer to neighboring yards or natural areas that are not fenced.
Chemical repellents. There are several repellents that work with varying efficacy, but unfortunately they need frequent reapplication and may smell bad and/or damage the plant. But this approach just shifts the problem to somewhere else – the deer still need to eat.
Harassment – dogs, noise, or water spray can chase deer out of a yard. But, like fencing, harassment only moves the problem to a neighbor’s yard, and doesn’t solve the problem.
Which Urban and Suburban Deer Management Methods Actually Work?
The Cornell University Study (download PDF) published in 2014 comprehensively reviewed the current state of the art about different strategies for coping with overabundant deer in suburban environments. More recent research by the Cornell team is summarized in this Video: Bernd Blossey talk at U of Michigan SEAS on Jan. 25, 2018: Impact and Management of White-tailed Deer in Our Neighborhoods, and in the publication Red Oak seedlings as Indicators of Deer Browse Pressure: Gauging the Outcome of Different White-tailed Deer Management Approaches
A comprehensive treatment of issues relating to the management of deer in populated areas can be found in the Association of Fish & Wildlife Agencies’ 2019 publication Methods for Managing Human-Deer Conflicts in Urban, Suburban and Exurban Areas
Some recent nonlethal fertility control studies include: